Answer:
<u>Antigenic drift</u> refers to the slow accumulation of genetic changes to an influenza virus over time. 
Explanation:
Antigenic drift is defined as the mechanism by which viruses undergo variation. This mechanism involves the slow accumulation of mutations in the viral genes, that are responsible for coding the antibody binding sites. This leads to the formation of a new strain of virus, which can't be inhibited by the old antibodies. Due to this, the virus can easily spread the disease. 
The antigenic drift occurs in the influenza A virus and also the influenza B viruses.
Therefore, <u>Antigenic drift refers to the slow accumulation of genetic changes to an influenza virus over time.</u>          
 
        
             
        
        
        
It prepares to fight danger or run from it. It identifies the primary source of danger.
        
                    
             
        
        
        
When there is myelosuppression, the suggestive finding is
there is a decrease in the platelets and red blood cells. Also called the bone
marrow suppression, myelosuppression is a common side effect of the treatment
of chemotherapy. When this side effect happens, there is a decrease in the production
of blood cells. The result which may be the effect of myelosuppression is a
decrease in one, two or all three types of blood cells. Most patients of
chemotherapy experience a decrease in red blood cells. Another effect is the
decrease of white blood cells by most patients. Myelosuppression will be
subcategorized as neutropenia when chemotherapy results to the reduction of
neutrophils which is a specific type of white blood cells. Thrombocytopenia is
the term for a drop in platelet numbers. This kind of suppression is not that common.  Only 10 percent of cancer patients undergo
the negative effects of this kind of suppression. 
 
        
             
        
        
        
Answer: A
Biomass energy can reduce the amount of organic material discarded in landfills.